I’ve been on the swim team for more than half a month in game, how much longer do i need to wait?
Could be a whole lot longer unfortunately! It took me most of the school year to trigger it. Swim team is especially tricky because you only have biweekly competitions, and I'm pretty sure progressing that storyline is locked behind doing well in competitions.
You'll know you're on the right track when coach starts offering you one on one training, then demands you do something sketchy during one on one training. Gaining relationship with The Quietly Determined Athlete may speed things along but I'm not 100% sure about that.